Neisserial porins inhibit human neutrophil actin polymerization, degranulation, opsonin receptor expression, and phagocytosis but prime the neutrophils to increase their oxidative burst

Porins are trimeric proteins that constitute water-filled pores that allow transmembrane diffusion of small solutes through the outer membrane layer of gram-negative bacteria. The porins are capable of inserting into the membranes of eucaryotic cells, and in the present study we have examined the in vitro effects on neutrophil functions of the following purified porins: meningococcal outer membrane protein classes 1 and 3 and gonococcal outer membrane protein 1B (P1B). The neisserial porins inhibited human neutrophil chemoattractant-induced actin polymerization and degranulation of both primary and secondary granules. The neutrophil expression of immunoglobulin G (IgG) Fc receptors II (Fc gamma RII; CDw32) and III (Fc gamma RIII; CD16), as well as the activation-dependent downregulation of Fc gamma RIII, were reduced by the meningococcal and gonococcal porins. The neisserial porins impaired the upregulation of complement receptors 1 (CD35) and 3 (CD11b) and inhibited the phagocytic capacity of neutrophils, as evaluated by the uptake of meningococci (strain 44/76) in the presence of patient serum containing known amounts of IgG against meningococcal porins. The porins also primed neutrophils to increase their intracellular hydrogen peroxide production in response to FMLP, whereas no such priming was observed if the neutrophil protein kinase C was stimulated directly with phorbol myristate acetate. The neisserial porins influenced neutrophil functions in a time- and concentration-dependent manner. The meningococcal class 1 outer membrane protein and the gonococcal P1B tended to alter neutrophil functions more than the meningococcal class 3 protein. Thus, the neisserial porins inhibited human neutrophil actin polymerization, degranulation, opsonin receptor expression, and phagocytosis but primed the neutrophils to increase their oxidative burst. It remains to be determined whether these in vitro observations reflect mechanisms that may be of importance for the interaction between neutrophils and Neisseria species in vivo.     

Effect of the sulfonylurea glyburide on glycogen synthesis in alloxan-induced diabetic rat hepatocytes

1. The effect of glyburide (glibenclamide) treatment on the liver glycogen levels of diabetic rats have been studied. 2. 3 weeks treatment with glyburide (5 mg/kg, orally) increased liver glycogen and decreased blood glucose levels. 3. The results of this study demonstrated that the sulfonylurea, glyburide is capable of exerting direct insulin-like effects on liver glycogen values in vivo.     

高速卷绕头网络控制系统的设计与实现

主控机、工控机、可编程逻辑控制器(PLC)和变频器(FC)构成的网络控制系统中，利用RS-232与RS-485接口实现主控机、工控机、可编程逻辑控制器和变频器之间的通信，具有成本低，易于实现多机联网控制．抗干扰能力强等优点。本文主要介绍了RS-232接口通信系统的设计方法与实现。     

可编程控制器在扩口成型机中的应用

扩口成型机在塑型管材生产线中属关键设备，本文探讨可编程控制器（PLC）及其温控模块在加热成型机中的实现技术，以及图示操作终端在加工设备中的应用。根据扩口成型机顺序控制的特点以及PLC及其组件齐全的硬件配置和软件功能，有针对性地具体研究扩口成型机的硬件配置和软件编制。     

钙锌复合稳定剂在UPVC型材中的应用研究

研究钙锌无毒复合稳定剂在PVC型材中的应用，并和传统铅盐稳定剂做了对比。结果表明：钙锌复合稳定剂为无毒稳定剂，制品的铅含量低，与铅盐稳定剂相比。生产工艺变化不大。产品能正常挤出。制品机械物理性能完全满足国标要求。     

酒店热水与空调系统联合供应解决方案探讨

本文介绍酒店热水与空调系统联合供应的几个优化方案,涉及到太阳能和热泵技术的应用原理与系统,应用中充分考虑两者的结合,选择最优的方案,做到最大限度地节能。